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Scientific American

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Scientific American

     January 1, 2009

    Completing the Cosmic Course

    Too bad you can't get frequent-flier miles for the hundreds of millions of miles you journeyed

    last year. Happy New Year! And don‘t feel bad about taking today off. After all, you‘ve

    traveled far. And I‘m not talking about the trip home from the party last night. According to NASA, just by being on the planet Earth in the last year, you‘ve zipped about 584 million

    miles around the sun to get back where you were. At an average speed of about 67,000 miles

    per hour. Again, not talking about the drive home last night. Of course, the trip was not a

    perfect circle. As Kepler showed, the Earth‘s orbit is an ellipse, with the sun at one of the two

    focal points. He also figured out the planet goes faster when it‘s at perihelion, nearer the sun,

    than when it‘s at aphelion, its farthest distance—which would explain why summer seems to

    zip by, except the seasons are a function of the tilt of the Earth‘s axis, not its different

    distances from the sun. And the Earth rotated 365 and a quarter times during its sweep

    around the sun. The trip took 8,766 hours. Or 31,557,600 seconds. Or 525,960 minutes just

    like this one. Steve Mirsky

    January 2, 2009

    Infecting Mosquitoes Before They Infect Us

    A study in the journal Science shows that infecting disease-carrying mosquitoes with the

    bacteria Wolbachia could be an effective way to cut their lives--and infectious capacity--short. Mosquitoes carry nasty diseasesdengue fever, West Nile, malaria. But the

    microbes that cause those diseases don‘t attach themselves to the mosquitoes and then

    immediately latch onto their next victim. They need time to grow and replicate in the

    mosquito before migrating to the bug‘s salivary glands. For example, the dengue fever virus

    takes about two weeks to incubate. So researchers from the University of Queensland in

    Australia and Central China Normal University are looking at a way to shorten the lives of

    mosquitoesand thus curtail their disease-transmitting ability. Researchers worked with a

    bacterial parasite called Wolbachia that infects numerous insect species. They spent

    three years adapting it to infect the Aedes aegypti mosquito, which carries dengue fever. It

    cut the lives of the mosquitoes by more than half. Those results were reported in the January

    2nd issue of the journal Science. The scientists say that because Wolbachia

    shortens a mosquito‘s life, the insects are that much less likely to pass on the diseases they

    carry. So a relatively inexpensive and effective human disease prevention program could be

    to mass-infect mosquitoes with Wolbachia. Which should make the medical

    community buzz. Cynthia Graber January 5, 2009

    Milky Way Now in Larger Size!

    A study presented at the meeting of the American Astronomical Society finds that we're

    moving 100,000 miles per hour faster in our galactic orbit than we thought, and that the

    Milky Way Galaxy is half again as massive as previously believed. We residents of the Milky

    Way should have a little extra skip in our step today. Turns out our home galaxy is much

    bigger and moving a lot faster than we previously thought. That‘s what researchers from the

    HarvardSmithsonian Center for Astrophysics reported January 5th at the meeting of the

    American Astronomical Society. Older studies of our galaxy‘s structure and motion used

    indirect measurements. But we can now use radio telescopes to directly observe certain

    features of the galaxy when we‘re in very different places in our orbit around the sun. And

    using traditional surveying methods, such as triangulation, researchers came up with the

new figures. First, we‘re moving about 600,000 miles per hour in our galactic orbit, a lot

    zippier than the old estimate of 500,000. And the Milky Way‘s total mass is about half again

    as much as we used to think. Which means we‘re about as massive as the nearby Andromeda Galaxy. The Milky Way‘s bigger mass does mean a greater chance of a gravity-driven

    collision with Andromeda. But if that clash occurs, at least now we‘re in the same January 6, 2009 | 2 comments

    weight-class. Steve Mirsky Dead Stars Tell of Rocky Planets

    A study presented at the meeting of the American Astronomical Society finds that the debris

    surrounding white dwarf stars is similar to the content of rocky planets--which means that

    rocky planets could be common to stars like our sun. Cynthia Graber reports

    If we want to learn more about our planet and other planets in the universe, we can get

    some help from stars that are long dead and gone. That‘s what U.C.L.A.‘s Michael Jura said

    at the American Astronomical Society meeting January 5th. His team used observations

    from NASA‘s Spitzer Space Telescope to investigate dead white dwarf stars. Dust and debris

    swirl around young stars. The pieces clump together to form asteroids and bigger planets.

    When a star like our sun finally dies, it blows itself up, bright red. Then it shrinks down into

    a skeleton of its former selfa white dwarf. The gravitational pull of these white dwarfs can

    attract nearby asteroids that then get pulverized. Eight different white dwarf systems were

    examined. In the surrounding asteroid dust, there was a mineral similar to olivine, which

    is common here on Earth. And there wasn‘t much carbon, also similar to the make-up of

    asteroids and rocky planets in our own solar system. The results suggest that the same

    materials that make up Earth and our solar system's other rocky bodies could be common in

    the universe. As could be rocky planets themselves. An insight for which we can thank dead

    stars. Cynthia Graber

    January 7, 2009

    Reflected Light Disrupts Animal Behavior

    A study in the journal Frontiers in Ecology and the Environment notes that reflected

    light--off of buildings or roadways--can be as disruptive to animal behavior as the direct

    light that attracts sea turtle hatchlings to begin life in the wrong direction. Man-made

    light sources can really throw animals for a loop. Moths can't tear themselves away from

    lightbulbs, and newly hatched sea turtles often shun moonlit ocean waves for the bright

    lights of inland cities. But a study in January's issue of the journal Frontiers in Ecology and

    says direct light sources are only part of the problem. Light that reflects off the Environment

    shiny urban surfaces, like roads, parking lots and buildings, has an equally devastating

    power to attract. That's because such polarized light means one thing to most

    animalswater. For example insects like dragonflies make nocturnal flights to lay their eggs using horizontally polarized light as a beacon. That light might bring them to a

    stream or pond, but a well-lit interstate is equally alluring. If enough insects lay eggs on the

    road instead of in the water, the entire food web can be disrupted. But there are ways to dim

    our influential lights, the scientists say. Bugs are less attracted to roadways with white

    hatch marks on the pavement. And light-colored curtains can keep birds from slamming

    into dark buildings. Simple fixes, really, to keep basic instincts from turning into fatal

    attractions. Adam Hinterthuer January 8, 2009

    Body Makes Own Aspirin Compound

    A study in the Journal of Agricultural and Food Chemistry finds that humans can

    manufacture their own salicylic acid, the major part of aspirin. Another study, in Nature,

    shows that plants make their own salicylic acid at wound sites. Aspirin is a popular

    painkiller, and chances are you have some in your medicine chest right now. You might

    even have some in your flesh-and-blood, put-a-shirt-on-it chest. Because a new study

    suggests that humans can make their own salicylic acid, which forms the bulk of aspirin‘s active ingredient. Scientists at Scotland‘s National Health Service previously observed that

    people can have salicylic acid in their blood even if they haven‘t recently swallowed an

    aspirin. Vegetarians have really high concentrations, which makes sense, given that plants

    make salicylic acid, so fruits and veggies are full of it. But their recent study suggests that

    not all of the chemical comes from the diet, because humans can take a precursor molecule

    and turn it into salicylic acidresults published in the Journal of Agricultural and Food

    . The researchers say that people might make salicylic acid to fight inflammation Chemistry

    or disease…which would also make sense…because plants make the stuff to fight off

    infections. In fact, a recent study published online in the journal Nature shows how calcium

    released at the site of an infection tells plants to ramp up production of the protective

    compound. Just Mother Nature‘s way of saying, ―Make two aspirin and call me when you

    flower.‖ —Karen Hopkin January 9, 2009 | 0 comments

    Male and Female Mosquitoes Synchronize Buzz

    A study in the journal Science finds that mosquitoes checking out mates synchronize their

    buzzing to the same frequency. Researchers hope to exploit this behavior for insect control.

    Have you ever turned off your lights and heard [mosquito buzz]? To you it‘s a sound that

    signals bites in the night. But to a male mosquito it‘s a love song, produced by a female

    seeking a mate. Now scientists from Cornell University find that males who answer that call

    join in the serenade. And the two sing in harmony as they check each other out. [Mosquitoes

    buzzing.] Working with Aedes aegypti mosquitoesthe pests that carry dengue feverthe

    scientists tethered individuals to a special insect pin and allowed them to fly past a

    potential mate. They found that females on their own whine at a frequency of 400 Hertz.

    Whereas single males buzz at about 600. But when the two come together, they perform a

    duet in which the beat of their wings reaches a frantic1200 hertz. [Tone.] Isn‘t it beautiful?

    Mosquitoes seem to think so. Which is a surprise, because researchers had previously thought

    that female mosquitoes were deaf. But the Cornell scientists found that mosquito ears are

    good up to 2000 hertz, results published in the January 9th issue of

    Science. Maybe that

    harmonizing could be exploited for controlling mosquito populations. Releasing into the

    wild males that can‘t sing could be a real buzz-kill. Karen Hopkin January 12, 2009

    Judging a Book by Its Genomes

    A study to be presented at the meeting of the Bibliographical Society of America shows that

    some medieval manuscripts can be tested to establish place and time of origin--because the

    pages are made from animal skins that offer up DNA evidence. Thousands of medieval

    European books survive to this day. Authors and scribes carefully handwrote the works on

    parchments made of animal skins. But the writers didn‘t always bother to sign and date

    their works. So we had no way of knowing where and when most of the documents are from.

    Until now. Researchers at North Carolina State University have demonstrated that they can

    reliably extract DNA samples from such parchments. Each manuscript offers up, they say, a

    wealth of genetic information, because as many as a hundred animals contributed skins

    for one book. The scientists propose recording DNA data from all books for which we do have

a reliable date and place of origin. These reference samples would create a DNA library of

    dates and locations. Then the mystery manuscripts could be compared against that DNA

    database. The North Carolina investigators are presenting the technique for dating old

    manuscripts at the upcoming annual meeting of the Bibliographical Society of America.

    And they‘re still working on improved techniques to harvest DNA while doing minimal damage to the original priceless parchments. A way to further illuminate those January 13, 2009

    illuminating books. Cynthia Graber

    Pterodactyls' Ptough Ptakeoffs

    Johns Hopkins researcher Michael Habib contends that the weight carried by most

    pterosaurs meant that they needed to push off the ground with all four limbs to achieve

    takeoff (in a study published in the German journal Zitteliana Reihe B: Abhandlungen der

    ). Bayerischen Staatssammlung fur Palaontologie und Geologie

    A bird in flight is a thing of beauty. Even their takeoffs and landings usually look

    effortless. But pterodactyls? Well, that‘s another story. Scientists have long assumed

    that pterodactyls, also called pterosaurs, flew just like birds, and launched

    themselves using their hind legs. Now a biologist at Johns Hopkins says that can‘t be

    true. Instead, he says that pterosaurs needed all four limbs for liftoff. Modern birds

    use their legs to launch and their wings to stay aloft. Once they‘re in the air, their

    hind limbs are essentially payload, carried along for the ride. That arrangement

    presents a problem. A bird‘s legs have to be muscular enough to get Tweety off the

    ground, but not so big that they drag him down. That limits how big a bird can be.

    Some pterosaurs, on the other hand, were the size of a giraffe. And looking at the

    bones of three different pterodactyl species, the Hopkins scientist concludes that

    there‘s no way those legs were strong enough to get that bulk airborne. Instead, he

    says a pterosaur used all four limbs, leapfrogging forward on its knuckles, to propel

    itself into the air. Maybe not a thing of beauty. But it must have been something to

    see. Karen Hopkin

    January 14, 2009

    Eavesdropping on Dolphins

    Inventor John Stuart Reid has patented a device he calls a CymaScope, which creates

    three-dimensional images of sound. He hopes to use it to identify specific dolphin sounds.

    When we think about how to represent sound visually, most of us probably picture those

    volume-dependent sine waves. But that‘s not how John Stuart Reid pictures sound. He‘s patented something called a CymaScope. And he‘s using it to help us learn more about how

    animals like dolphins communicate. The CymaScope contains a thin film of

    waterbasically a membrane. Sound—even at frequencies humans can‘t hear—is directed

    at the water. The water vibrates in response, and a camera records the vibration. The end

    result is a spherical image of sound patterns. Reid is working with Jack Kassewitz, a dolphin

    researcher in Florida. Kassewitz has recordings of dolphins in specific situationsfor

    instance, what he knows to be distress calls from a variety of individual animals. Those calls

    have been imaged by the CymaScope. Kassewitz also plans to have a number of different

    dolphins echolocate on a ball. He hopes that‘ll give us a visual picture of how dolphins

    recognize a ball. It might sound far-fetched, but Reid and Kassewitz believe these sound

    images will provide a library of what we might call dolphin words. Which could one day let

    us communicate with them with their own vocabulary. Cynthia Graber

    January 15, 2009

Getting a Teeny-Tiny Grip

    In a report in the Proceedings of the National Academy of Sciences USA, Johns Hopkins

    University researchers discuss their invention of a "microgripper," a metallic device the size

    of a speck of dust that can float through tissue and latch on to individual cells. Forget the

    scalpel, researchers at Johns Hopkins University have created a tool that can move easily

    through tissue, potentially making biopsies much less invasive. They call it a "microgripper."

    And the wireless, dust-particle sized device is able to grab single living cells from

    hard-to-reach places. Their report appeared in the online early edition of the Proceedings

    . The researchers assembled out of tiny metallic plates a of the National Academy of Sciences

    "palm" with six three-jointed "fingers." This metal hand is truly tiny: just one-tenth of a

    millimeter in diameter. In the lab, scientists used magnets to pilot the microgripper through

    a tube of animal tissue and up to a living cell. Then, by applying heat as a trigger, the joints

    softened and the "fingers" closed around the cell. The researchers hope the device will have

    applications beyond cell retrieval. It could be used to manufacture microchips or deliver

    medicine to specific locations in the body. But first, they must refine its motor skills. Right

    now, the microgripper can only grab—it can‘t let go. And we're still years away from

    shrinking Raquel Welch to go in after it. Adam Hinterthuer January 16, 2009

    Mars Is Alive! (Geologically, Biologically or

    Both)

    A study in the journal Science finds that methane is being released at specific places on Mars--which means that Mars has geologic activity, biological activity or both. There‘s definitely methane on Marsand there are seasonal variations of how much is being released into the thin Martian atmosphere. Which means that Mars is still active

    geologically. Or that deep underground, something is or was alive. Or both. NASA and

    university scientists report the finding in the January 16th issue of the journal Science.

    Researchers studying the Martian atmosphere discovered and measured methane levels

    over the last few years, using telescopes with infrared spectrometers. These instruments

    identify chemical compounds by analyzing their unique light absorption properties. They

    found that Mars methane is being released as concentrated plumes at specific latitudes.

    Such plumes could come from various kinds of geological events. Underground bacterial

    communities could also be producing the methane. Or now-extinct living systems could

    have produced the methane long ago, with it only now being released through pores or

    fissures created by seasonal temperature variations. On earth, 90 percent of the methane in

    the atmosphere comes from the biochemical activity of life. The rest is produced by

    geochemical processes. The Mars methane‘s specific isotopic makeup could reveal whether its

    origins are biochemical or geological. Cynthia Graber January 19, 2009

    Gene Lowers Infection Chance by Changing

    Behavior

    A study in the journal Science finds that roundworms with a particular gene have lower rates of infection--not because they have stronger immunity, but because they prefer to live

    in environments with fewer microbes. A new study with worms shows that some have a gene

    that helps them stave off infections. Not through some kind of biochemistrybut by

    C. elegans,

    one strain that is commonly used in the laboratory, another that was isolated in Hawaii.

    The laboratory strain got fewer infections than the Hawaiian strain. That‘s because the lab changing their behavior. Scientists were studying two strains of the roundworm worms have a particular version of a gene called NPR-1. But the way the gene works is a bit

    of a surprise. You might think that a gene involved in fighting infections must somehow

    enhance an animal‘s immune response. But you would be wrong. Because a current study,

    published in the January 16th issue of Science, shows that‘s not the case. Instead, the

    scientists showed that the NPR gene found in healthier worms made them picky about their

    location. They stayed clear of places where oxygen is scarce. As it happens, those are the

    neighborhoods where bacteria hang out, including the bugs that can cause disease. So the

    gene made the worms prefer germ-free locales. So, take a tip from a worm. If you want to

    avoid what‘s out there this winter, just don‘t go out there. —Karen Hopkin January 20, 2009

    Bacteria Can Use Viruses to Spread Toxin Gene

    A study in the journal Science shows that staph bacteria are able to use viruses to insert their

    dangerous genes into the genomes of other species of bacteria. For years, scientists and

    physicians have been up in arms about the rise in antibiotic resistance. Seems that many

    bacteria, devious buggers that they are, are able to share genetic informationincluding, say, the instructions for destroying penicillin. Well, if that‘s not bad enough, scientists from

    the N.Y.U. School of Medicine have found that some bacteria can use viruses to help them pass

    along the recipe for their favorite toxin, results published in the journal Science. Like

    humans, bacteria are also prone to infection by viruses. And most of these virusescalled

    bacteriophage, or phage for shortmake their bacterial victims sick. Or even dead. But in

    the laboratory, the scientists discovered that Staphylococcus aureus, the bug that causes

    toxic shock syndrome among other things, can actually co-opt phage, using them to shuttle

    the gene for toxic-shock toxin to another bacteria, in this case Listeria. That‘s doubly nasty,

    because Listeria on its own causes food poisoning, so if it added toxic shock to its repertoire,

    well, that would be one seriously bad bug. Whether Staph aureus can pull off this stunt

    outside the lab‘s not clear. But in this particular battle, ya gotta hope the viruses come out

    on top. Karen Hopkin

    January 21, 2009

    "We Will Restore Science to Its Rightful Place"

    Pres. Obama's inaugural address noted the importance of science, a coherent energy policy

    and basic curiosity. Pres. Barack Obama: ―Our health care is too costly…and each day

    brings further evidence that the ways we use energy strengthen our adversaries and

    threaten our planet… ―We will build the roads and bridges, the electric grids and digital

    lines that feed our commerce and bind us together. We will restore science to its rightful

    place and wield technology's wonders to raise health care's quality and lower its costs. We

    will harness the sun and the winds and the soil to fuel our cars and run our factories. And

    we will transform our schools and colleges and universities to meet the demands of a new

    age… ―Our challenges may be new, the instruments with which we meet them may be new, but those values upon which our success depends, honesty and hard work, courage and fair

    play, tolerance and curiosity, loyalty and patriotismthese things are old. These things are true.‖ —Produced by Steve Mirsky

    January 22, 2009

    Does fMRI See the Future?

In a study published in the journal Nature, researchers find that functional magnetic

    resonance imaging may measure not only what the brain is doing, but what it is about to

    do. For decades, scientists have used an imaging technique called functional magnetic

    resonance imaging, or fMRI, to chronicle the brain in action. But a study in the January

    22nd issue of Nature suggests that fMRI might show more than what the brain is doingit

    might reveal what the brain‘s about to do. FMRI studies assume that blood flow in the brain

    correlates with neuronal activity. Active brain cells need nutrients, which are brought to

    the cells by freshly oxygenated blood. But in the new study, scientists found that fMRI also

    detects increased blood flow in brain regions that aren‘t active—but that may be in the near

    future. The researchers trained monkeys to perform a specific visual task. And they found

    that, even when the animals were sitting in the dark waiting for the test to begin, fMRI

    nevertheless revealed an increased blood flow to the monkeys‘ visual cortex. The study

    suggests that fMRI data may be a lot more interesting than we thought. Scientists may be

    looking at their imaging data in a way that‘s too simplistic. And fMRI may not be

    measuring exactly what we thought it did. What will they think of next? Maybe fMRI can tell.

    Karen Hopkin

    January 23, 2009

    Crickets Con Connubial Conquests with

    Chemistry

    In a study published in the journal Biology Letters, researchers found that male crickets

    impress their dates with gifts of food that are light on nutrition but heavy on appetite

    stimulants. As Valentine‘s day approaches, remember, it‘s the thought that counts. Just ask a

    decorated cricket. Because according to a study published in the January 21 issue of the

    journal Biology Letters, the nuptial gift that male crickets use to woo their women is just a handful of amino acidsin a whole lotta water. Many insects use a food offering to win over a potential mate. For crickets, the giftbag serves to distract the female while the actual

    sperm transfer takes place. As long as she‘s busy eating, she won‘t reach around and remove

    that little packet of swimmers. And the longer she feeds, the more sperm will make it through.

    And, presumably, the more little crickets that male will sire. But the male, of course, wants to

    get the biggest bang for his buck. So his goal is to minimize what he lays out in his token of

    appreciation. The solution? The cricket‘s gift contains a small sampling of amino acids,

    mostly nonessential glycine, and 84 percent water. But those amino acids act as an appetite

    stimulant, which causes the female to spend more time enjoying her nutritionally empty

    snack. It‘s a cheap gift, but it works. Because nothing says ―be mine‖ like a gooey glob of

    glycine. Karen Hopkin

    January 26, 2009

    South Asia Brown Cloud Is Homemade

    In a study published in the journal Science, researchers found that a brown pollution cloud

    over south Asia and the Indian Ocean is largely the result of burning wood and dung for

    cooking and heating. There's a huge, gunky brown cloud that lingers over south Asia and

    the Indian Ocean each winter. It‘s been known to cause respiratory diseases and even

    cancers in India and China. But scientists didn't really know what was in it. Now they do.

    Researchers from Stockholm University and colleagues published the results in the January

    23rd issue of the journal Science. The cloud contains black particles called carbonaceous aerosolsbasically carbon soot. The team used radiocarbon analysis to figure out what

    parts of the soot come from biomass and what comes from fossil fuels. Biomass typically comes

from burning forests for agriculture or burning wood in stoves. And fossil fuel particulates

    come from sources such as diesel engines or burning coal. The investigators were surprised to

    discover that a large percentage of the soot, from almost half to two-thirds, comes from

    burning biomass like wood and dung for cooking and heat, rather than from coal power

    plants. Scientists say the good news is that these particles only remain in the atmosphere for

    January 27, 2009 a few days or weeks at a time. So once societies can figure out how to reduce biomass burning,

    that brown sooty hazeand the illnesses it causesmight disappear. Cynthia Graber Eat Less, Remember More

    In a study published in the Proceedings of the National Academy of Sciences, researchers

    showed that elderly women who ate low-calorie diets improved their memories. You may

    have noticed that as you get older, you start forgetting more stuff: like, where you left your

    glasses, or the names of your children. Well, if you‘re fed up with those senior moments, put

    down that pastrami sandwich. Because a new study, published in the January 27th issue of

    the Proceedings of the National Academy of Sciences, shows that cutting calories actually

    improves memory in older folks. Calorie restriction lets lab animals live longer. And these

    hungry critters tend to be healthier, too: with lower cholesterol, better insulin sensitivity,

    and even slower cognitive decline. But these diets can be draconian. And it hasn‘t been

    clear whether they‘d offer the same benefits to people. In this study, scientists asked 50 elderly

    women to cut the number of calories they consumed by a third. After three months, the

    researchers found that the dieters were not only slimmer, but they were better than they had

    been at memorizing lists of words. They also had better insulin levels and fewer markers of

    inflammation, which suggests that keeping those things under control may help keep the

    brain fit. It‘s one of the cruel ironies of aging: if you want to remember your favorite

    restaurants, the less you should eat at them. Karen Hopkin January 28, 2009

    Horning In on Triceratops In a study published in the journal PLoS ONE, researchers conjecture that the three horns of Triceratops were often used for fighting--because museum specimens show much more

    scarring than in the horns of a related species. Triceratops, as the name suggests, were huge

    dinosaurs adorned with three horns on their heads. Scientists now say those horns may have

    been a sort of battle bludgeon. Andrew Farke is a curator at the Raymond M. Alf Museum of

    Paleontology in California. He became curious about that headgear. Farke and colleagues

    wanted to investigate whether Triceratops fought each other with their horns. Which posed a problem: obviously, we can‘t go back in time to watch the animals interact. So the

    researchers resorted to some techniques out of a Cretaceous CSI. They examined more than

    400 museums specimens of Triceratops and another closely related one-horned dinosaur called Centrosaurus. They scanned the skulls for injuries around where Triceratops might

    have locked horns and wrestled. Their assumption was that if the horns were just for display,

    both species would show few scars. But the Triceratops had 10 times more skull injuries than

    their Centrosaurus cousins. The most likely explanation is that they probably jabbed each

    other in the head while fighting. The researchers published their findings in the journal

    Public Library of Science ONE. They also caution that the horns could have served more than

    one purposeperhaps fighting and flaunting. Cynthia Graber January 29, 2009

    Wireless Networks Are Soft Virus Targets

In a study published in the Proceedings of the National Academy of Sciences, researchers

    warn that viral attacks on wireless networks can easily spread to tens of thousands of routers.

    We‘ve all gotten e-mails warning us about nasty computer viruses. Maybe you even have

    antivirus software installed on your machine. Well, now scientists say that our wireless

    networks are particularly vulnerable to infection, especially in densely populated urban

    areas. The use of Wi-Fi routers has become increasingly commonplace, as more people get

    online at home, at school, at the coffee shop. And these wireless networks are an excellent

    target for computer viruses, because they‘re always on, always connected to the Internet,

    and don‘t have specific software to protect them. The scientists simulated the infection of

    real wireless networks in a handful of U.S. cities, including San Francisco, Chicago, New

    York and Boston. They found that the infection of just a small number of routers triggered

    an outbreak, with the virus spreading to tens of thousands of routers within a week, most

    within the first 24 hours. The results are published in the Proceedings of the National

    . Wireless networks are weakened by a general lack of security, Academy of Sciences

    including a failure to change the default password. So if you want to keep your network

    virus-free, at the very least choose a password that‘s hard to guess. Like Bosco. —Karen

    Hopkin

    January 30, 2009

    New Brain Cells Get Time-Stamped

    A study published in the journal Neuron indicates that newborn neurons in the hippocampus get a sort of time stamp. So events that occur at the same time are forever

    linked in our minds. You probably remember exactly what you were doing when you first

    heard the news on 9/11. That‘s because the brain has ways to file information so that things

    that happen at the same time are forever linked in our minds. Now a study published in the

    journal Neuron says that newborn cells in a structure called the hippocampus help us

    remember concurrent events. The hippocampus is part of the brain that allows us to lay down

    new memories. And about ten years ago, scientists were surprised to find that new neurons

    pop up in this region every day, even in adult animals and people. But what do these new

    cells do? Scientists turned to computer modeling to help them find out. They put in what they

    knew about the behavior of these new cells, which start out like puppies that get totally

    excited over every little thing, and eventually mature into more discerning members of

    neuronal society. And they found that the hyperactivity of these excitable young cells, which

    react with great gusto to everything that goes on, could help stamp memories with a sort of

    ―time code‖ that indicates which things happened together. So if you still remember what

    you were eating when you dumped your loser boyfriend, you can thank your newborn

    neurons. Karen Hopkin

     February 2, 2009

    Museums Dogged by Wrong Animal Walks

    A study published in the journal Current Biology found that even natural history museums often don't know the details of how animals walk, and incorrectly display animals in

    motion as a result. Karen Hopkin reports. For images and more information, see Scientific

    contributing writer Carl Zimmer's blog item at snipurl.com/sciamwalk If you American

    have a dog, you know you gotta walk it. But do you know how it walks? Well, if you have no

    idea which foot Fido puts forward when, you‘re in good company. Because according to a

    study published in the journal Current Biology, even places like natural history museums get it wrong half the time. Studies published back in the late 1800s showed that all

    four-legged animals walk the same way. They start by moving forward their left hind leg,

    followed by the left front leg. Then they repeat the sequence on the right-hand side. Different

    animals differ in the timing of their steps. The reason they walk that way is for stability.

    Lifting one leg at a time leaves three feet on the ground, forming a nice stable tripod to

    stand on. But not everyone seems to know that, even folks who should. Scientists looked at

    300 depictions of animals walking—in museums, anatomy texts, and even children‘s toys.

    And they found that nearly half the time these images get it wrong. For a toy, that kind of

    February 3, 2009 inattention to detail might mean that Rex has a tendency to roll over. But for museums to

    mess up like that? They just don‘t have a leg to stand on. —Karen Hopkin

    Water Conservation Unwitting Mosquito Ally

    In a study published in the journal Functional Ecology, researchers warn that people

    capturing rainwater in drought-ridden areas are also providing breeding grounds for

    disease-carrying insects. Mosquitoes have an unwitting new ally in the war on infectious

    diseasesconservationists. Turns out that, for mosquitoes carrying dengue-fever,

    environmentally conscious humans may be aiding the invasion. That‘s the finding of a

    study published in the journal Functional Ecology.

    In Australia, severe drought has led citizens to capture and store rainwater. While that's

    good for water conservation, the resulting array of water-storage tanks provides the perfect

    breeding ground for an army of mosquitoes.

    The researchers say mosquitoes around the world are already moving into areas

    experiencing the warmer, wetter effects of climate change. Adding accessible pools of water

    to countless backyards will only help increase the insect's range.

    For Australia's dengue mosquitoes, the researchers are also concerned about the

    development of drought-resistant eggs. Other insects have already evolved eggs that can

    withstand dry-spells. If the dengue mosquito follows suit, even the arid Outback could

    someday promote mosquito-borne illness. But there's a powerful way to interfere with the

    entire process: simply cover up water containers. Adam Hinterthuer

    February 4, 2009

    Largest Snake Rattles Paleontology

    In a study published in the journal Nature, researchers announced the finding of the fossil remains of the largest snake that ever lived--possibly reaching 45 feet and 2,500 pounds.

    Indiana Jones (―I hate snakes—I hate ‗em!‖) would have totally despised a snake that lived

    some 60 million years ago. Because researchers working in Colombia have found the fossil

    remains of a snake that would have been up to 45 feet long, weighing in at perhaps 2,500

    pounds. That makes it the biggest snake ever to have slithered across the Earth. The

    announcement appears in the February 5th issue of the journal Nature. The creature has

    been dubbed Titanoboa.

    The fossil snake bones were found in an open-pit coal mine, along with its prey, which

    included turtles and crocodiles. Now, a snake this big could only live where the average

    temperature was between 30 and 34 degrees Celsius. So we gain info also about the climate

    at the time. Study leader Jason Head from the Smithsonian said, ―The discovery of

    Titanoboa challenges our understanding of past climates and environments, as well as the

    biological limitations on the evolution of giant snakes. This shows how much more

    information about the history of Earth there is to glean from a resource like the reptile fossil

    record.‖ —Steve Mirsky

    February 5, 2009

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